fix #3542: node task logs: query correct node for tasks in clusters

fix #3542: node task logs: query correct node for tasks in clusters

While refactoring, we forgot to replace the 'localhost' URL (which is
valid for PMG/PBS) with the actual nodename we have in Proxmox VE.

Do this by setting the correct URL in the viewModel right at the
start of the initComponent

We now also have the possibility to overwrite the url if we want

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>